<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <script src="https://lf3-cdn-tos.bytecdntp.com/cdn/expire-1-M/vue/2.6.14/vue.js" type="application/javascript"></script>
</head>
<body>
    <div id="app">
      <el-input ref="inputRef" v-if="isShow"></el-input>
      <button @click="onClick">按钮</button>
    </div>
</body>
<script >
    Vue.component('el-input', {
      template: `
        <input ref="inputEleRef"/>
      `,
      methods: {
        focus(){

          this.$refs.inputEleRef.focus()
        }
      },
    })
    new Vue({
        el: '#app',
        data() {
            return {
              isShow: false
            }
        },
        methods: {
          onClick(){
            this.isShow = true
            this.$refs.inputRef.focus()
          }
        }
    })
</script>
</html>
